There are five billion light bulb sockets in the United States. This market has fostered numerous devices and schemes to control lights.
The most common controls are wall switches near entrances to rooms. This location is adequate for on-off switches because one normally uses them entering or leaving the room. The room entrance wall switch location is not always adequate for dimmer switches because the need to change light level usually arises when inside the room, often while sitting or lying down, and not when entering and leaving the room. Hence the concept of a remote control has arisen, analogous to a television remote control or a wall switch on a nightstand. Some remote control devices are little more than novelties, controlling a single device at a fixed frequency and easily interfered with by a second remote control nearby. At the other extreme are elaborate and quite expensive “home automation” systems with remote controls having dozens of buttons and often a small screen for user interface. For example, the remote control allows a user to configure the home automation system to turn on a coffee pot the next morning. A lesser expensive and elaborate system is the remote control sold by Lutron®. This is a single remote controller configured to control a single wallswitch. It has five buttons for ON, OFF, brighter, dimmer, and a preset light level. It is infra-red based and, for added convenience (and/or confusion), it is compatible with some other infra-red remote control systems. The remote control is large enough to fit in the hand of a user, but small enough to be easily misplaced. If the user forgets to take it with him/her, it can end up in some other location where it is no more convenient than the wallswitch it is supposed to replace.